Inkjet printers are image-formation devices that form images on media, such as sheets of paper, by ejecting fluid, specifically ink, onto the media in accordance with the images desired to be formed on the media. Most inkjet printers operate by ejecting ink on a swath-by-swath basis, where a swath can extend from one side of a media sheet to the other side, and has a given height. One or more printheads of an inkjet printer first are scanned over a current swath of the media, ejecting ink as they are scanned over this swath. The media is then typically advanced by one swath, so that the printheads are able to be scanned over and eject ink onto the next swath.
Inkjet-printing technology has sufficiently advanced so that media advancement on a swath-by-swath basis can be precisely controlled. Therefore, the swaths of the resulting image formed on a media sheet cannot usually be individually discerned. However, exceptions remain. For instance, bar codes, which are series of vertical lines of varying thickness, that are formed over two consecutive swaths are difficult to print precisely. As a result, the part of a bar code formed on a first swath and the part of the bar code formed on a next swath may be able to be discerned, owing to the vertical lines of the bar code enhancing any differentiation in the printing of the different swaths.
For example, small gaps between swaths, or small overlaps between swaths, resulting from less than perfect media advancement, are visually accentuated by bar codes. The inkjet printheads may also scan the width of the media sheet in one direction to form the first swath containing one part of a bar code and be scanned in the opposite direction to form the next swath containing another part of the bar code. Slight imperfections in the ejection of ink due to the different directions in which the printheads were scanned may result. Although such imperfections are difficult to discern with most image features formed on the media, they are more readily apparent with bar codes, resulting in a decrease in perceived image quality.